incumbent presidents from confrontations often stumgle as did president ronald reagan in '84. >> i did avoid i'm afraid in my previous answer also. >> reporter: president obama seemed to have initially thought it went well. >> this was a terrific debate. >> reporter: quickly he talked to aides and realized he had not brought his "a" game. this is on me he later told top advisers and since then he's been studying the video of that night with the goal of a more energetic and crisp performance. while the obama campaign dismisses it other top democrats say pressure is now on vice president biden, a win by congressman paul ryan could create a dynamic of energized challengers squaring off against tired incumbents. and, diane, vice president biden is in debate prep holed off in a delaware hotel reading the book that ryan co-authored contract young guns" and practicing the attack lines the president did not use. there is more room for vice presidential candidates to use those attack lines because their approval ratings do not matter as much. diane? >> jake, as you said, the pressure really on